Spinal implants are devices that may be implanted within a spine. Some spinal implants may be surgically inserted within the spine. For example, some spinal implants may be inserted between vertebrae during spinal surgery. Spinal surgery may be performed to alleviate back pain. In some cases, back pain may be severe, and even debilitating. In some scenarios, a medical patient's back pain may be due to damage, disease, or inflammation affecting the vertebrae or intervertebral discs. For example, disabling back pain may arise from disruption of the disc annulus. In some examples, back pain may be a result of instability of the vertebral bodies surrounding a damaged intervertebral disc.
In some cases of severe back pain, mechanical limitation to the movement of vertebrae may be advantageous. In some scenarios, treatment for back pain may require surgical disc removal. For example, damage to intervertebral disc tissue may require surgical removal of the disc nucleus. In some cases, instability of the vertebral bodies that surrounded the removed disc may result. In an illustrative example, persistent inflammation or instability due to a removed disc may result in a recurrence of disabling back pain after surgery. In some cases, the likelihood of back pain recurring after disc removal may be reduced and back pain recurrence mitigated by stabilization of the adjacent vertebral bodies subsequent to disc removal. For example, vertebrae adjacent to the removed disc may be surgically fused with the aid of a fusion device implanted between vertebrae.
Some spinal implant surgery may have time-limited benefits. For example, some spinal implants may subside into the vertebral endplates as time passes after fusion surgery. In some examples, spinal implant subsidence into the vertebral endplates may be a result of limited contact area between the implant and endplates. In an illustrative example, spinal implant subsidence into the adjacent vertebral endplates may result in back pain due to reduced spacing between the vertebral bodies. Some spinal implants limit the vertebral endplate surface area in contact with the implant, which may limit bone growth. Limited bone growth between the fused vertebrae after implantation may result in limited spinal stability. Some spinal implants may be composed from multiple separate components that must be individually assembled together within the intervertebral disc space, making optimal placement of the spinal implant difficult in some scenarios.